To decrease the microleakage under packable composite which is inherent to this materials use of flowable composites have been recommended. This study evaluated effect of flowable composites on the fatigue bond strength of packable composite to dentin.
Methods:
Coronal dentin of 20 intact human third molars was ground flat using 600grit SiC paper and bonding agent was applied as manufacturer’s instruction (single bond-3M, USA). The teeth were divided into 2 groups and treated as follows; Group1: Filtek Flow (3M, USA)+ P60(3M, USA) composite, group2: P60 composite. After 500cycle of thermocycling,each main groups were divided into two subgroups. One of these subgroups was subjected to100,000 load cycling of 50 N. The other subgroup used as control. Microtensile bond strength test was performed (Bisco Inc USA). Failure patterns were observed using a stereomicroscope. Data subjected to Student t-test for statistical analysis.
Results:
Before fatigue test, mean microtensile bond strength was 25.49MPa for group1and 35.63MPa for group2. After fatigue test, mean microtensile bond strength was 24.37MPa for group1 and 31.36MPa for group2. The difference between two subgroups of each main group was not statistically significant.
Conclusions:
Using flowable composite as a liner in packable composite restorations did not iaffect bond fatigue resistance to dentin.